<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style type="text/css">
        html{   
        width: 100%;   
        height: 100%;   
        overflow: hidden;   
        font-style: sans-serif;   
    }   
    body{   
        width: 100%;   
        height: 100%;   
        font-family: 'Open Sans',sans-serif;   
        margin: 0;   
        background:url('blackboard.jpg');
        background-size:100% 100%; 
        background-attachment:fixed;
    }   
    #login{   
        position: absolute;   
        top: 50%;   
        left:50%;   
        margin: -150px 0 0 -150px;   
        width: 300px;   
        height: 300px;   
    }   
    #login h1{   
        color: #fff;   
        text-shadow:0 0 10px;   
        letter-spacing: 1px;   
        text-align: center;   
    }   
    h1{   
        font-size: 2em;   
        margin: 0.67em 0;   
    }   
    input{   
        width: 278px;   
        height: 18px;   
        margin-bottom: 10px;   
        outline: none;   
        padding: 10px;   
        font-size: 13px;   
        color: #fff;   
        text-shadow:1px 1px 1px;   
        border-top: 1px solid #312E3D;   
        border-left: 1px solid #312E3D;   
        border-right: 1px solid #312E3D;   
        border-bottom: 1px solid #56536A;   
        border-radius: 4px;   
        background-color: #2D2D3F;   
    }   
    .but{   
        width: 300px;   
        min-height: 20px;   
        display: block;   
        background-color: #4a77d4;   
        border: 1px solid #3762bc;   
        color: #fff;   
        padding: 9px 14px;   
        font-size: 15px;   
        line-height: normal;   
        border-radius: 5px;   
        margin: 0;   
    }  
        
        
        
        </style>
    <script LANGUAGE="JavaScript">

        function openwin() {
            
        if(document.getElementById("w_flag").value=="1"){
            alert("注册失败，用户名长度：1~10，密码与学号不能为空")
            
        }
        if(document.getElementById("w_flag").value=="2"){
            alert("用户已存在，请重新输入")
            
        }
        if(document.getElementById("w_flag").value=="3"){
            alert("学号已存在，请重新输入")
        }
        }
        </script>


</head>
<body onload="openwin()">
    <input type="hidden" value="{{w_flag}}" id="w_flag">
<div id="login">
<h1>欢迎注册</h1>
<form method="post" action="/register">
    <!-- 用户名：<br><input name="username" type="text"><br>
    密码：<br><input name="password" type="password"><br> -->
    <input type="text" required="required" placeholder="用户名" name="username"></input>  
    <input type="password" required="required" placeholder="密码" name="password"></input>
    <input type="text" required="required" placeholder="学号" name="sno"></input>  
    <!-- <input value="注册" type="submit"> -->
    <button class="but" type="submit">注册</button>
</form>
</div>
</body>
</html>
